Enables fragment shader test for impeller (fixes mat2 on vulkan) by gaaclarke · Pull Request #181013 · flutter/flutter

gaaclarke · 2026-01-15T00:13:28Z

This rearranges the packing of mat2 fields in structs which was causing an existing fragment shader test to fail.

The test still doesn't work on Metal, but this PR fixes it for Vulkan. I suspect the fix for metal may be similar but since the uniforms aren't in a virtual struct the code isn't hitting this fix.

issue: #180873

Pre-launch Checklist

I read the Contributor Guide and followed the process outlined there for submitting PRs.
I read the Tree Hygiene wiki page, which explains my responsibilities.
I read and followed the Flutter Style Guide, including Features we expect every widget to implement.
I signed the CLA.
I listed at least one issue that this PR fixes in the description above.
I updated/added relevant documentation (doc comments with ///).
I added new tests to check the change I am making, or this PR is test-exempt.
I followed the breaking change policy and added Data Driven Fixes where supported.
All existing and new tests are passing.

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Code Review

This pull request enables a fragment shader test for Impeller by fixing an issue with mat2 reflection on Vulkan. The core change is in reflector.cc, where logic is added to correctly handle mat2 types according to std140 layout rules. This is supported by a new unit test and a corresponding fragment shader. Additionally, some Dart tests are now enabled for Impeller, with one being skipped on Metal as it's not yet supported. The code quality is also improved with better documentation and consistent styling. The changes are well-structured and effectively address the issue. I have one minor suggestion to improve code readability.

engine/src/flutter/impeller/compiler/reflector.cc

walley892

Wild. Main thing is it would be nice to have another test with the fragment shader stuff.

engine/src/flutter/impeller/fixtures/mat2_test.frag

engine/src/flutter/impeller/compiler/reflector.cc

walley892

Very slick programming by steamboat willie

auto-submit · 2026-01-15T17:56:13Z

autosubmit label was removed for flutter/flutter/181013, because - The status or check suite Linux linux_license has failed. Please fix the issues identified (or deflake) before re-applying this label.

auto-submit · 2026-01-15T19:39:42Z

autosubmit label was removed for flutter/flutter/181013, because - The status or check suite Mac mac_unopt has failed. Please fix the issues identified (or deflake) before re-applying this label.

…lkan) (flutter/flutter#181013)

Roll Flutter from 48c2475 to bfc9041eb118 (173 revisions) flutter/flutter@48c2475...bfc9041 2026-01-23 [email protected] No longer exiting the application when the RegularWindow is destroyed + resolving the window created promise after runWidget (flutter/flutter#181339) 2026-01-23 [email protected] Remove unnecessary Material import from dialog_test.dart (flutter/flutter#181249) 2026-01-23 [email protected] Roll Skia from 8e516fe6828f to db10db8bd55f (1 revision) (flutter/flutter#181379) 2026-01-23 [email protected] Reset TextFormField to initial value after state change (flutter/flutter#181199) 2026-01-23 [email protected] Roll Dart SDK from 980b2b41d36e to e82d7ad1855e (1 revision) (flutter/flutter#181375) 2026-01-23 [email protected] Roll Skia from 3e86f377d300 to 8e516fe6828f (4 revisions) (flutter/flutter#181370) 2026-01-23 [email protected] Remove unnecessary Material import from sliver_visibility_test (flutter/flutter#181248) 2026-01-23 [email protected] Add bottom navigation bar item semantics label (flutter/flutter#180577) 2026-01-23 [email protected] Make topGap not required for CupertinoSheetTransition (flutter/flutter#181269) 2026-01-23 [email protected] Roll Fuchsia Linux SDK from b4cLyhuxciUC-4zCJ... to n7NohL9DPpEuPjNt9... (flutter/flutter#181365) 2026-01-23 [email protected] Roll Dart SDK from 806f04638561 to 980b2b41d36e (1 revision) (flutter/flutter#181364) 2026-01-23 [email protected] Reland hybrid views test (flutter/flutter#181336) 2026-01-23 [email protected] Revert DropdownMenu non-nullable breaking change (flutter/flutter#181074) 2026-01-23 [email protected] Fix leaks in `flutter_test` tests (flutter/flutter#180879) 2026-01-23 [email protected] Re-enable fragment_shader_tests.dart 'Shader Compiler appropriately pads vec3 uniform arrays' test on Vulkan (flutter/flutter#181292) 2026-01-23 [email protected] [ Tool ] Fix `update-packages` failing due to mismatched dependencies between flutter_tools and the framework (flutter/flutter#181335) 2026-01-23 [email protected] [Impeller] Make dynamically created shader metadata for runtime effects consistent with metadata for built-in shaders (flutter/flutter#181201) 2026-01-23 [email protected] Broaden the applicability of `Color` fix_data rules from flutter/painting.dart (flutter/flutter#181093) 2026-01-23 [email protected] Fixes macOS App.framework not being codesigned or find framework (flutter/flutter#181348) 2026-01-22 [email protected] Roll Fuchsia GN SDK from NAEC5tfgSl8g94nwp... to JLBh4Z9PKsjIJcqDU... (flutter/flutter#181139) 2026-01-22 [email protected] Roll Dart SDK from ab4640ea82e9 to 806f04638561 (2 revisions) (flutter/flutter#181347) 2026-01-22 [email protected] Add ExpansibleController.toggle method. (flutter/flutter#181320) 2026-01-22 [email protected] Fixes Typo in codebase (flutter/flutter#181256) 2026-01-22 [email protected] Roll Skia from 4766615bcc96 to 3e86f377d300 (3 revisions) (flutter/flutter#181346) 2026-01-22 [email protected] Make sure that a Hero doesn't crash in 0x0 environment (flutter/flutter#180954) 2026-01-22 [email protected] Reland "Fix capitalization of the path to FlutterWindowControllerTest.mm in the macOS platform build script" (flutter/flutter#181200) 2026-01-22 [email protected] Roll Skia from 6e9746be8c4a to 4766615bcc96 (3 revisions) (flutter/flutter#181331) 2026-01-22 [email protected] Fix remove material import textfield (flutter/flutter#181254) 2026-01-22 [email protected] Add FlutterFramework as an Xcode SwiftPM local package override (flutter/flutter#179512) 2026-01-22 [email protected] Roll Dart SDK from 7bd4c68b625c to ab4640ea82e9 (1 revision) (flutter/flutter#181324) 2026-01-22 [email protected] Roll Packages from d80c60e to 9010299 (9 revisions) (flutter/flutter#181323) 2026-01-22 [email protected] Roll Dart SDK from 2d53a77adc5d to 7bd4c68b625c (2 revisions) (flutter/flutter#181316) 2026-01-22 [email protected] Roll Skia from 3f6949bc5780 to 6e9746be8c4a (2 revisions) (flutter/flutter#181311) 2026-01-22 [email protected] Roll Skia from ef6efc358b4a to 3f6949bc5780 (2 revisions) (flutter/flutter#181307) 2026-01-22 [email protected] Roll Dart SDK from 5d7c8faf2e41 to 2d53a77adc5d (1 revision) (flutter/flutter#181305) 2026-01-22 [email protected] [Material] update hourFormat to use Dart 3 switch expression (flutter/flutter#181041) 2026-01-22 [email protected] Use null-aware elements in cupertino/nav_bar.dart (flutter/flutter#181237) 2026-01-22 [email protected] Roll Fuchsia Linux SDK from b2KIEXVAlEqImQ9VO... to b4cLyhuxciUC-4zCJ... (flutter/flutter#181297) 2026-01-22 [email protected] Roll pub packages (flutter/flutter#181295) 2026-01-22 [email protected] Enables fragment shader test for impeller (fixes mat2 on vulkan) (flutter/flutter#181013) 2026-01-21 [email protected] Roll Dart SDK from 366200db1aa1 to 5d7c8faf2e41 (4 revisions) (flutter/flutter#181290) 2026-01-21 [email protected] Roll Skia from b5ec89e31f59 to ef6efc358b4a (19 revisions) (flutter/flutter#181289) 2026-01-21 [email protected] fix description for semantics finders (flutter/flutter#181214) 2026-01-21 [email protected] Make sure that an Icon doesn't crash in 0x0 environment (flutter/flutter#181021) 2026-01-21 [email protected] Make sure that a GridPaper doesn't crash in 0x0 environment (flutter/flutter#180906) 2026-01-21 [email protected] Bring Linux coverage out of bringup (flutter/flutter#181280) ...

…tter#181013) This rearranges the packing of mat2 fields in structs which was causing an existing fragment shader test to fail. The test still doesn't work on Metal, but this PR fixes it for Vulkan. I suspect the fix for metal may be similar but since the uniforms aren't in a virtual struct the code isn't hitting this fix. issue: flutter#180873 ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. **Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.  [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

Reland `Enabled some disabled impeller fragment shader dart tests` (flutter#180788) relands flutter#180759 changes since revert: 1) waits for async tests now 1) keeps 2 tests that don't pass on impeller disabled - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. **Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.  [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md Enables fragment shader test for impeller (fixes mat2 on vulkan) (flutter#181013) This rearranges the packing of mat2 fields in structs which was causing an existing fragment shader test to fail. The test still doesn't work on Metal, but this PR fixes it for Vulkan. I suspect the fix for metal may be similar but since the uniforms aren't in a virtual struct the code isn't hitting this fix. issue: flutter#180873 - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. **Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.  [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md Account for vec3 padding in Metal (flutter#181563) Re-landing of flutter#181340 incorporating flutter#181550. Vec3 uniforms on the metal backend are vec4-aligned. This PR accounts for that padding. --------- Co-authored-by: gaaclarke <[email protected]> Fixes getUniformX for Vulkan (flutter#181286) Does what it says on the tin! This PR adds struct member information to the runtime flatbuffer format. This allows dart code to introspect structs at runtime. Also modifies the runtime_stage tests to verify formats for all supported uniform types. Bubbles up struct member information to dart, and uses that information to grab struct members in `getUniformX` related functions. This is necessary on Vulkan because all uniforms are packaged into a single struct. Also re-enables tests - [ ] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [ ] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [ ] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [ ] I signed the [CLA]. - [ ] I listed at least one issue that this PR fixes in the description above. - [ ] I updated/added relevant documentation (doc comments with `///`). - [ ] I added new tests to check the change I am making, or this PR is [test-exempt]. - [ ] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [ ] All existing and new tests are passing. Organize and update fragment shader uniform tests. (flutter#181822) Adds more comprehensive testing for setFloat and getUniform* on fragment shaders. Deletes redundant tests. Fixes getUniformVecX indexing errors. Update web ui fragment shader tests (flutter#181877) Adds a bunch of tests for uniform setting functionality for custom fragment shaders on the web. Deletes redundant tests. Fixes a discovered issue in the uniform offset calculation. We were previously using the `location`, which is the integer offset of the uniform, not the offset in floats.

gaaclarke added 9 commits January 14, 2026 14:03

Fixes mat2 layout in uniform reflection

86cc103

fixed padding space

f7d5c2f

format

b323cea

updated docstring

bbc0edd

fixed argument comments

79b2976

renamed mat2

be049de

skipped for metal

b973d80

made skip more clear

0873aa2

turned on "FragmentShader with uniforms renders correctly" too

f8e7b77

github-actions bot added engine flutter/engine related. See also e: labels. e: impeller Impeller rendering backend issues and features requests labels Jan 15, 2026

gaaclarke requested review from flar and walley892 January 15, 2026 00:14

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gaaclarke added 2 commits January 15, 2026 08:34

added comment

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added mat2 test

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gaaclarke requested a review from walley892 January 15, 2026 17:07

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Merge branch 'master' into mat2-fix

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Merged via the queue into flutter:master with commit 867339e Jan 22, 2026
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gaaclarke deleted the mat2-fix branch January 22, 2026 01:01

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Roll Flutter from 48c247582e45 to 2dc633eb1168 (142 revisions) flutter/packages#10850

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867339e93 Enables fragment shader test for impeller (fixes mat2 on vu…

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…lkan) (flutter/flutter#181013)

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Roll Flutter from 48c247582e45 to baa9e3215220 (143 revisions) flutter/packages#10853

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867339e93 Enables fragment shader test for impeller (fixes mat2 on vu…

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…lkan) (flutter/flutter#181013)

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Roll Flutter from 48c247582e45 to dbed04aa32e5 (144 revisions) flutter/packages#10856

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867339e93 Enables fragment shader test for impeller (fixes mat2 on vu…

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…lkan) (flutter/flutter#181013)

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Make FragmentShader shader with array uniforms renders correctly pass on metal #181333

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Roll Flutter from 48c247582e45 to bfc9041eb118 (173 revisions) flutter/packages#10862

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867339e93 Enables fragment shader test for impeller (fixes mat2 on vu…

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Enables fragment shader test for impeller (fixes mat2 on vulkan)#181013

Enables fragment shader test for impeller (fixes mat2 on vulkan)#181013
gaaclarke merged 13 commits intoflutter:masterfrom
gaaclarke:mat2-fix

gaaclarke commented Jan 15, 2026 •

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